(1) Field of the Invention
This invention relates to turnstiles, gates and the like, such as are particularly designed for controlling pedestrian passage through a controlled zone, and in particular, to such devices as incorporate a remotely controllable locking means to bar such passage.
(2) Description of the Prior Art
Turnstiles, gates and like devices are commonly used to control passage, either into or out of a controlled zone. For example, such gates are frequently encountered at the entrance to subways, theaters, amusement parks and the like. More recently, such devices have also been utilized in conjunction with antipilferage systems at the exits of libraries, etc., to prevent the passage of persons upon the detection of an antipilferage marker.
Due to fire and safety concerns, such gates, particularly when positioned as a barrier to an exitway, are desirably provided with means such that locking mechanisms in the gates may be overcome in case of emergency. Typically, prior art gates have been provided with shear pins which couple the pivoting portions of the gate to the locking mechanism. Upon application of an excessive force, the shear pins may then be severed, allowing the gate to be opened. Such shear pins are undesirable in that they require manual servicing of the gate to replace the pins after such an event. Other prior art gates have avoided the use of shear pins by providing a friction coupling between the pivoting members and a member being selectively locked. Such gates are also undesirable in that manual servicing is still required to reindex the pivoting members at the closed position with respect to the locking mechanism.